1. Field of the Invention
This invention relates to a lossless compression technique and an apparatus in which an image produced by error diffusion is predictively run length encoded and decoded.
2. Discussion of Related Art
Data compression systems have been used to reduce costs associated with storing and communicating image data. However, conventional compression methods yield very little compression when the input image is halftoned by error diffusion. Error diffusion is an important technique for digital halftoning. It usually generates images with superior quality. Due to irregular, high frequency noise patterns introduced in the process, it is very difficult to compress error diffused images. For example, conventional run length based techniques, such as CCITT Group3 and Group4 formats used in facsimile operations, are inappropriate for compressing error diffused images since they cannot suitably handle short run lengths which are dominant in error diffused images.